Heater unit for air circulating heaters



9, l1945. w. c. coLEMAN'ET/u. 2,385,437

HEATER UNIT FOR AIR CIRGULATING HEATERS y Filed Feb. v1:5, 1941 2 sheets-sheet 1 37 i l 5 @i 39 ii I /3 |40 zo l [I t il 2 i' e@ I 6 y /Z l q l 2 735544 5 4f ff 22 Jug. 2.

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I BY 9 33' 2g M l] Y vATTORNEY Oct. 9, 1945.. w. Q COLEMAN ETAL' l HEATER UNIT FOR .AIR CIRCULATING- HEATERS Filed Feb. 1s, 1941 sheets-Sheet 2 e $19145'v l y 2,386,431'

A William C. Coleman and Russell Martin, Wichita,

Kans., assignors to The Coleman Lamp and Stove Company, Wichita, Kans., a corporation of Kansas Y e Application February 13', 1941, Serial No. 378,704 -v A 'This invention relates to aircirculating heaters,

and more particularly to a heater unit therefor,

and hasfor its principal. object tciprovide a heater unit having greater and more efcient heat transmitting surface fori a given sized heater.

Other objects of the invention are to provide a heater unit construction wherein the hot gases of combustion are distributed substantially equally to all of the heat transmitting surfaces; to provide a heater unit constructed to reduce heat losses through the flue; to provide a heater unit construction with two distincty heat transmitting areas, one area constituting the outside walls of the heater unit and the other 'a vertical duct extending through the heater unit and which cooperates with `a partitionin the heater unit to effect thesubstantially uniform distribution of hot gases to all heat exchange surfaces; and to provide a heater unit construction wherein increased turbulence of the hot gases is effected.

In one assembly the tube may be soV located and sized to eect four functions, namely,. a draft tube to circulate air, a partition to effect longer travel of hot gases, a largely increased heat transmitting surface, and a vertical distribution of hot gases for more even heating of the surfaces.

.In accomplishing these and other objects of Vthe invention, -as hereinafter pointedA out, we

have provided improved structure, the preferred forms of which are illustrated in the accompany' ing drawings, wherein:

Fig. l is a perspective view 4of a circulating. air heater equipped with a heater unit having a combustion chambena heat exchange tube andl an exhaust chamberconstructed in accordance with" the present invention, part of the outer heater walls being broken away to 'better illustrate the construction. e

PIE. 2 is' a vertical section through theheater.

V'V is a horizontal section onV the line 2 3 of Fig. 2. Referring morefin-'detail to the drawings:

VI `designates a heating device such as a circulating air heater equipped with. a heater unit having a combustion chamber and heatV exchange tube embodying the features of the'present .invention. Thefheater includes an outer geek-et. z, having eide wens Hana from; and," rear-,walls B -O connected by a grill'top 1 and a 5obottom). The bottoni I -is carried above the naeronfr'eet l and .is provided with airmlet openings Il and--II arrangedsubstantialiy coaxially withthe section and air tubey circulating described. l' I'he lowerportions of the front and sidewalls are provided with air inlet openings I2 to admit air into the interior of the outer jacket 2 forupward circu. lation about 'the heater unit and discharge through the grill 1.

Suitably supported within burner and heater unit I3, including a combustion chamber Il Afor products of `combustion.

The heater unit isshaped to provide maximum exterior heat transmitting surfacefor the size of the casing without restrictingthe circulating air passageways 'therearound i' The heater unit, therefore, includes a casing Ihaving front and rear walls I5-I6 and substantially semicylindrical side walls I'l'-I8, the walls being formed of sheet material having relatively high heat conductivity and are of suiiicient height to give the desired heatexchange area. The walls carry upper and lower end top and bottom plate members I9 and 20 which are properly secured thereto to provide substantially gas or' air-tight joints. A

Extending through the casing Vof the heater e. unit, substantially coaxially with the side wall I8, is a tubularstructure 2| having its ends supported within openings 22 and 23 of the top and bottom plates ofthe heater unit. The tube forms a barrier to ow' of hot products of combustion and is of a diameter relatively to the diameter of the wall I8 to provide a narrow passageway 24 therebetween for the products of combustio The passageway 24 extends fronither bottom to the top of thel heater unit and wherein the effective'area is approximately equal to but preteJ erably slightly larger than the area ofthe flue outlet 25 which is connected with the rear' wall I6 of the heater unit midway the width thereof,

the'larger cross-section in the passageway being desirable because the flue gases are hotter and more expanded in the passageway than at the ue outlet.

The relative size of the elongated passageway to the iiue opening, together 4with the relative locationsy thereof, control passage of hot gases through the heater unit so that the gases are substantially uniformly distributed over the heat transmitting surfaces, as later described. The tube 2|, extending completely through the heater unit, provides for flow of air therethrough and cooperates with the exterior walls of the heaterl lunit to' increase the'heat transmitting areas thereof.

vBelow the combustion chamber section of the heater una, at the opposite side thereof and substantially in coaxial alignment with the axis of the semicireular wall Il, is a cylindrical"'burner the jacket is a the fire-pot.

'the heater unit .above -the burner.

defined by the walls of the heater Unit. the wall f cumi'erentially about' the outer yface of the heat exchange tube 2| through the passageway 24 thus contacting both the `wall of the up-draitv heat exchangetube land the inner surface of the heaterv unit side wallv I6 to reach theue through the expanded space which is termed the of the burner chamber 26 to provide an air passageway 32 therebetween. The bottom of the burner pot is closed by a concavo-oonvex bottom 33 arranged with the concave side uppermost to collect a pool of fuel' which is admitted through an inlet opening 34 that is connected by a pipe 35 with a .constant level control and safety valve 36 which is supplied with fuel from a tank 31 mounted onthe rear wall of the heater jacket.

egress chamber. 'I'he passageway 24, being relatively narrow and extending from the top to the bottom of the heater unit, causes the hot gases to spread out along the entire height of the heat- 4 er unit. 'I'he hot gases are thus caused to now over the entire circumference of the up-draft 'I'he burner pot is provided with a low flame v burner ring 38 and has an upper high iiame burner ring 39 supported on an outwardly turned iiange 4o of the burner-pot. The flange 40 suspends the pot within the opening of the bottom of the heater unit.

tube as well as the entire inner surface of the corresponding semicylindrical end'wall of the heater unit. After passing through the narrow passageway 24, .the hot gases flll the enlarged space termed the egress chamber formed between the partition 46 and periphery of the heat exchange tube which chamber facilitates the discharge through the ilue opening. The relatively long'travel and large heat transmitting area con- Formed in the top of the combustion chaln- I ber section, in alignment with the fire-pot, is a door opening 4|, having a depending circumferential flange 42 containing a gasket ring 43.

Seated on the gasket ring 43 is a lid 44 which is movably supported on a hinge assembly 45 to permit access to the combustion chamber section of the*heater unit for lighting the burner.`

In orderto assuretravel of the products of com-v bustion through the passageway 24,-the interior of the heater unit is provided'with a partition' 46 which extends the height thereof and has one edge 41- welded to the inner face of the rear side wall I6 at the side nearest the burner pot andv the other edge extending angularly to the periphery of the tube 2| to cooperate with the tube and rear wall in providing an egress chamber 46' which is closed fromthe combustionv chamber section'except through the passageway 24, as

shown in Fig.3. The partition 46 thus cooperates with the air iiow tube 2| to form an egress chamber between the outlet of theipassageway- -24V and the ue connection, which Vegress chamber is substantially c tensive with the height of the passageway. th this arrangement, the

combustion chamber is completely closed froml the egress chamber except through' the passageway so that all of the hot products of combusftion are yforced to travel around thepassageway substantiallyv uniformly of the height thereof.

The egress chamber slows up action of the products of combustion and 'facilitates entrance of products of combustion into the flue connection without restriction and might be termed a plenum chamber with the exception that when tacted by the hot gases assures larger heat transmission through the walls of the heater unit and heat exchange tube. Itis also obvious that the heat exchange tube, in cooperation with the partition 46 lengthens the ilow of the gases until I they have had time to give up a greater amount of heat, thereby reducing temperature of the flue gases and effecting greater efficiency. The relatively large heat exchange are?l lalso provides more surface contact with the air being circulated with the result that the heat exchange is carried on more vrapidly and a greater amount of air is therefore moved through the heater to better distribute the heat into the room spaces being heated.

While we have'shown a liquid fuel burning device in connection with aheater unit having a heat exchange tube. it is obvious that the invention is equally as well adapted to other types of fuel such as gas. It is also obvious that the heater unit is readily applied either to a circulating heater which is locatedH ectly in the room to be heated, or in a small furnape which may be installed exteriorly ofthe room, for ex-` -ample below the floor of the room.

From the foregoing it is obvious that we have provided a heating unit including a combustion chamber and heat exchange tubewherein the heat exchange surfaces are greatly increased over ordinary heaters of a given full capacity and the flow of the hot gases is better controlled Patent is:

inoperation it contains a pressure belowatmos- -1/ When the heater illustrated in Figs. 1't`o vil4 inclusive is placed'in operation, the fuel supply is established from the tank to the fire-pot so-that a pool of fuel collects on the bottom'thereof.

This fuel is th'en. ignited through the door open-l ing 4|. The air supporting combustion is admitted to the burner chamber through the open` ing 28 and through perforations in the sides 'of The products kof combustion resulting from the burning fuel ll the space in This space,

of the heat exchange tube, and the Apartition 46 is termed the combustion chamber and all the hot gases therefrom are caused toV travel cirto more evenlyheat allsuriaces thus promoting eilciency of operation and more rapid circulation of airl to better heat spaces for which the heater or furnace is'installed.

What we claim and desire to secureby Letters 1. A heater unit including a casing having a top and bottom connected by front,l rear, and `side walls, at least one of said side walls being 'curved transversely, an air flow tube extending through the casing and havingits ends supported by said top and bottom and having a curved side portion spaced from and cooperating with the curved side wall to provide a curved passageway y therebetween having an inlet adjacent the front wall and an voutlet adjacent the rear wall, said inlet and outlet being substantially coextensive with the height of said walls, a partition extending from the top to the bottom of the casing and .from the rear wall to the airflow tube for cooperating With the air ilow tubel in dividing the casing into a combustion chamber at the inlet end of the passageway and an egress chamber at the outlet end of said passageway. a vent connection from said egress chamber having a ow capacity substantially equivalent to the flow capacity of said passagewayy for eiecting spread of hot products of combustion along the entire -height of said curved side wall and air flow tube,

and a burner fat the bottom of the combustion chamber. I l.

2. A heater unit including a casing having a top and bottom connected by front, rear, and side Walls, at least one of said side walls being curved transversely, a cylindrical air flow'tube extending vertically through the casing and having its ends supported by said top and bottom I substantially coaxial with said curved side wall and having a curved side portion spaced. froml and cooperating with the curved side wall to pro-l vide a curved passageway therebetween having an inlet adjacent the front wall and an outlet adjacent the rear wall extending the full height 20 of the casing, said rear wall having a vent opening adjacent the outlet end of the passageway, a partition extending from the top to the bottom of the casing and extending angularly from the rear wall on the side of the vent opening opposite said passageway outlet to the air ow tube for cooperating with the air flow tube in dividing the casing into a combustion chamber at the v inlet e'nd of the passageway andan egress cham- 

